Free NGSS Phenomenon Bank
49+ real-world phenomena for K-12 science, organized by grade band, NGSS disciplinary core idea, and topic. Free to use, share, and adapt.
Use these to swap tired phenomena in OpenSciEd, SEPUP, or any NGSS-aligned curriculum. Each phenomenon is anchored to observable, puzzling events that drive genuine scientific questions — not just demonstrations.
Licensed under CC BY 4.0 — free to use with attribution to Almanack.
What makes a phenomenon work in NGSS?
Observable
Students can see, hear, feel, or directly experience it — or see a compelling representation of it. Abstract examples don't anchor inquiry.
Puzzling
It raises a genuine 'why?' or 'how?' question that can't be answered with prior knowledge. If students already know the answer, it's not a phenomenon — it's a fact.
Scientifically rich
The explanation requires the specific DCIs and practices you're teaching. The phenomenon is a vehicle for building that understanding, not a tangent.
Browse by grade band
Grades K–24 phenomena
| Topic | DCI | Phenomenon |
|---|---|---|
| Forces & Motion | PS2 | Why do some balls roll further than others? |
| Matter | PS1 | Why does ice cream melt faster on a hot day? |
| Plants & Animals | LS1 | Why do some plants grow toward windows? |
| Weather | ESS2 | Why are puddles gone after a sunny day? |
Grades 3–54 phenomena
| Topic | DCI | Phenomenon |
|---|---|---|
| Forces & Motion | PS2 | Why can a small ramp make it easier to push a heavy box onto a truck? |
| Matter | PS1 | Why does sugar disappear when you stir it into water? |
| Ecosystems | LS2 | Why do some animals only come out at night? |
| Earth & Space | ESS1 | Why do shadows change length throughout the day? |
Grades 6–824 phenomena
| Topic | DCI | Phenomenon |
|---|---|---|
| Forces & Motion | PS2 | Why do some cars crumple in a crash while others don't? |
| Forces & Motion | PS2 | Why does a soccer ball curve when kicked with spin? |
| Forces & Motion | PS2 | How do rock climbers stay on vertical surfaces? |
| Energy | PS3 | Why does a metal spoon get hot faster than a wooden spoon in boiling water? |
| Energy | PS3 | Why do black cars get hotter in sunlight than white cars? |
| Energy | PS3 | How do hand warmers work — and why do they stop working? |
| Waves & Information | PS4 | Why can you hear a train before you see it? |
| Waves & Information | PS4 | Why does your voice sound different in a bathroom than in a field? |
| Matter & Its Interactions | PS1 | Why does iron rust but gold doesn't? |
| Matter & Its Interactions | PS1 | Why does bread rise when you add yeast? |
| Heredity | LS3 | Why do identical twins sometimes look different as they get older? |
| Heredity | LS3 | Why do some families have more left-handed members? |
| Natural Selection | LS4 | Why are there so many different beak shapes in birds? |
| Natural Selection | LS4 | Why are most cats in the same city neighborhood the same color? |
| Ecosystems | LS2 | Why did wolves change the rivers in Yellowstone? |
| Ecosystems | LS2 | Why do some fish glow in the deep ocean where there is no sunlight? |
| Cells | LS1 | Why does a cut on your skin heal without leaving a scar sometimes? |
| Cells | LS1 | How can a starfish grow back a missing arm? |
| Earth's Systems | ESS2 | Why are there no mountains as tall as Everest in the eastern United States? |
| Earth's Systems | ESS2 | Why is the ocean saltier in some places than others? |
| Weather & Climate | ESS2 | Why do deserts often form on the eastern side of mountain ranges? |
| Weather & Climate | ESS2 | Why is it colder at the top of a mountain even though it's closer to the sun? |
| Earth's History | ESS1 | Why do scientists find marine fossils on mountaintops? |
| Space Systems | ESS1 | Why does the moon look different every night? |
Grades 9–1217 phenomena
| Topic | DCI | Phenomenon |
|---|---|---|
| Forces & Motion | PS2 | Why do satellites stay in orbit without falling? |
| Forces & Motion | PS2 | Why does a spinning top not fall over immediately? |
| Energy | PS3 | Why do some materials feel cold even at room temperature? |
| Energy | PS3 | Why does a refrigerator feel warm on the back? |
| Waves & Information | PS4 | How does a microwave oven heat food without making the container hot? |
| Matter & Its Interactions | PS1 | Why does a glow-in-the-dark toy need to be 'charged' in light first? |
| Matter & Its Interactions | PS1 | Why do fireworks produce different colors? |
| Heredity | LS3 | Why can two brown-eyed parents have a blue-eyed child? |
| Heredity | LS3 | Why do some genetic diseases skip generations? |
| Natural Selection | LS4 | Why are bacteria becoming resistant to antibiotics? |
| Natural Selection | LS4 | Why do peppered moths in industrial areas look different from those in rural areas? |
| Ecosystems | LS2 | Why did the removal of sea otters devastate kelp forests? |
| Cells | LS1 | Why do some cancer cells survive chemotherapy when most don't? |
| Earth's Systems | ESS2 | Why are some earthquakes so much more destructive than others of the same magnitude? |
| Weather & Climate | ESS2 | Why have summers been getting hotter in cities faster than in rural areas? |
| Earth's History | ESS1 | Why did so many species go extinct at the end of the Cretaceous period? |
| Space Systems | ESS1 | Why don't all planets have moons? |
How to use this phenomenon bank with OpenSciEd
OpenSciEd units are built around anchor phenomena — real-world events that drive the unit storyline. Each unit phenomenon should be puzzling to students, connected to the DCIs for the unit, and personally relevant enough to sustain curiosity for 3–5 weeks.
When swapping a phenomenon in OpenSciEd, the replacement should: (1) address the same disciplinary core idea, (2) lend itself to the same science practices used in the unit (investigation, data analysis, modeling), and (3) maintain the storyline's logical progression from observation to explanation.
Want Almanack to do the swapping work for you? Start free — paste in any OpenSciEd lesson and tell us the new phenomenon, and Almanack will update the lesson to fit.
Need Almanack to swap a phenomenon for you?
Paste your OpenSciEd lesson, pick a new phenomenon from this bank, and Almanack updates the full lesson to fit — in under 2 minutes.
Try it free — no credit card needed